What temperature is it where you are right now. I find that SMBC is very finicky when it come to temperature. If it is too hot it can get runny and soft, too cold it curdles and seperates. Was it the right constisincy when you first made it? If the constincy was okay when you first made it then it will just need the right temperature and more beating. I usually can change the temperature by cold or hot cloths around the bowl or a bowl of ice or hot water below the mixer if you have a professional Kitchen Aid. I hope that helps.

Thanx Rowingmom for all the info! I added too much Bailey's Irish cream. Even after 8 tbsp it still wasn't strong enough. Lol. When I tried piping it, I could see very small beads of liquid sitting on top of the frosting. Anyhoo, I stuck it in the freezer to use later on then I wondered if I could add more butter. I know i can add more SMBC to it to thicken but just wanted to know if I could add more butter instead.

I think what is giving you the problem is the amount of alcohol. Too much wants to seperate out. I don't know about the butter I would suggest next time using some of the lorann oils there is a Keoke Coffee Flavor that is supposed to be like Kalua and you would only need a little bit to get a stronger flavor. You can order them online. I hope this helps.